Calling all arse mechanics (or people who just know shit)

DexterPunk · Post by **DexterPunk** » Sat Apr 16, 2011 11:37 am

I have a really annoying rattle coming from my car, especially when powering on. It seems to be coming from the exhaust, near the front. I got the exhaust on my car changed over maybe 6 months ago. And I sourced the catalytic converter for the swap over. I actually think this might be the issue. Me and a mate jacked up the car to have a look and you could hit the cat with your hand and replicate the rattle. I'm fearing that the problem is internal and the honeycomb has come loose inside. Very irritating since its only about 6 months old. The cat is a Magnaflow, from all reports I can find, they are one of the better manufacturers out there. Surely this isn't normal? Is there something that could of caused it to happen?

I called the exhaust place I used, and the guy there suggested that I should maybe think about an all steel cat rather than ceramic. The part would cost me $430, and $480 installed. That seems like a fuck tone of cash. The high flow magnaflow cat was about $180 online. Now everything I read suggests that steel cats are pretty awesome, so no doubt it's an expensive part. But really that seems a bit of overkill... surely my hairdressers lancer shouldn't be killing ceramic cats.

Any advice/experience would be welcomed.

Cheers guys.

Post by **Bauer** » Sat Apr 16, 2011 1:32 pm

No your car should not be "killing cats" of any kind. I think your part has failed. period.

It shouldnt matter the type of cat. I have no experience with a steel cat so I dont know the gains, but you shouldnt have to go down that path. There are a lot of cars over 20 years old that would still have the original cat.

As for what could cause a cat to fail outside of a manufactured defect are things like actual damage caused by hitting something but usually it is raw fuel that melts the honeycomb. Faulty O2 sensor, incorrectly adjusted ECU etc etc.

It is up to you if spending $450+ is worth it for the upgrade but you shouldnt have to upgrade cos your car cant handle a ceramic cat.

Post by **Bauer** » Sat Apr 16, 2011 1:33 pm

But you are sure it isnt one of the heat shields around the cat right? Those welds are known to break.

macca · Post by **macca** » Sat Apr 16, 2011 5:06 pm

I would suggest check the heat shield, they can been bloody annoying the rattle they get, took a couple of attempts to fix on my car.

Takumi · Post by **Takumi** » Sat Apr 16, 2011 5:30 pm

When you hit the cat with your hand, are you sure the rattle was coming from inside it, and not another part of the exhaust hitting against something?

Righteous · Post by **Righteous** » Sat Apr 16, 2011 6:27 pm

I had an issue with an old car where I went through 2 or 3 cats. The issue was that the engine was running too rich, or something like that. The car was a pos and wasn't worth the effort to fix it.

DexterPunk · Post by **DexterPunk** » Sun Apr 17, 2011 12:05 pm

Thanks heaps Bauer... I agree that there really should be no need for a steel cat. I'm tempted to just get another magnaflow (I've seen them for $99 online, a universal for small to medium cars) and just get that fitted. Perhaps the one I got had some damage while being shipped to me.

As mentioned if there's an issue with the car running too rich or lean etc then I don't want to buy a new one and wreck it. Although it's due for a service anyway, I'm guessing they can check all that when it goes in.

$430 was the price for the steel cat, $480 installed. That seems like a hell of a lot. I've seen steel cats online for half that price. High end stuff for skylines etc. I don't need anything like that.

As for a rattle from the heat shield... I don't think so. It really does sound internal. I don't think it's coming from anywhere else either. I could be wrong, but either way it's getting looked at on Wednesday at the exhaust place. They said it wouldn't cost anything to jack it up and have a look.

The advantage of paying all that cash for the metal one and not supplying a part, is that it's then their issue if it fucks up again in 6 months time. Part of me is just inclined to fork out the cash instead of looking around for my own part and driving around with a horrible rattle while I wait for it all.

TIMMY30 · Post by **TIMMY30** » Mon Apr 18, 2011 12:45 am

First of all i would be contacting magnaflow and seeing about a warranty. Secondly please dont fork out all that cash for a cat from that bloke, hes taking you for a massive ride. When i had my SS BOTH my highflow cats didnt cost the price hes charging you for one. I would go to a different exhaust shop. Get their opinion on whether or not its the internals of the cat. Then i would contact magnaflow and find out about a warranty. 6 months is not good enough.
Have you noticed a power drop at all? If the cat is failing inside it should be partly blocked up in there.

Just my 2cents.

Tim

DexterPunk · Post by **DexterPunk** » Mon Apr 18, 2011 7:46 am

Cheers mate, yeah I'm not gunna pay that sort of money. Seems ridiculous.

Yeah im going to contact magnaflow... Or the site I bought it from to try and get a refund. Problem is, I have nfi where the receipt would be. Ill have to hope they accept a credit card statement as proof of purchase.

I'll ask these guys when they look at it how much it is for a ceramic high flow cat instead. If they quote me anything over about $250 installed I'll look for someone else to do it.

DexterPunk · Post by **DexterPunk** » Mon Apr 18, 2011 7:47 am

Oh, and if there's a power drop it's not very noticeable.

DexterPunk · Post by **DexterPunk** » Tue Apr 19, 2011 12:37 pm

Car is going up on the jacks tomorrow to see what the issue is.. same place that quoted $480. Im not paying it, but ill let them tell me what the issue is while I 'think about it'. I'm really hoping it's just the heat shield... but i doubt it.

I called up another exhaust place.. http://sportsexhaust.com.au/" onclick="window.open(this.href);return false; and they said they nearly choked when I said $480 even for a metal cat. The dude there over the phone said they had a metal one there that I could do anything to in terms of use what ever fuel I like, or bad tuning won't wreck it if thats the issue. And quoted $350 installed. Thats starting to sound a bit more believable and something I'm considering as it could potentially last the life of the car. He said its a bit of a catch 22... bad tuning is often the reason for a cat being destroyed... but they need a properly working one on the car to tune it. He said if i chuck on another ceramic, its likely to just shit itself again. It may be a little bit of an over exaggeration I'm guessing, but then I'm also guessing exhaust places need to watch their back a bit in terms of warranty. If some dude comes in and gets a new cat, but doesn't go and get his car serviced for 6 months, he will most likely be back there demanding a new one. So I guess thats why both places are suggesting a metal one.

Quincy · Post by **Quincy** » Wed Apr 20, 2011 12:22 pm

What fuel are you running?

Does this rattle/sound occur under load? ie, hooning up a hill?

Under normal acceleration? or heavy acceleration?

DexterPunk · Post by **DexterPunk** » Thu Apr 21, 2011 9:34 am

Normal power it will rattle... If the revs get up a bit it will stop. Even at idle it will rattle.

It's been confirmed as a stuffed cat. Some uber metal racing cat is being fitted today. Not that I think I'll get any power gains at all.. Simply want one that won't die if the car has some tuning issues. $350 fitted vs $227 for a ceramic. It's more money but at least I'll have some confidence in it.

Apparently this new one can have an optional O2 sensor fitted. What does this do?

petey · Post by **petey** » Thu Apr 21, 2011 10:33 am

I assume it would let you know if you were running too rich for the cat...stab in the dark :P

VTRacing · Post by **VTRacing** » Fri Apr 29, 2011 12:28 pm

But if the ECU doesn't know what to do with the input I'd suggest it's a waste of time.

DexterPunk · Post by **DexterPunk** » Fri Apr 29, 2011 4:15 pm

I didn't get that anywho. But worked out well car sounds really nice now, and actually does run a bit better, probably largely due to the semi blocked up cat. But happy it's done and out the way.

A.R.S.E.